Association between cirrhosis and aneurysmal subarachnoid hemorrhage.

Objective: Cirrhosis has been associated with nontraumatic subarachnoid hemorrhage (SAH). We sought to evaluate the specific association between cirrhosis and aneurysmal SAH.

Methods: We performed a retrospective cohort study using a sample of Medicare claims data from 2008 to 2015. Cirrhosis was defined using a validated diagnosis code algorithm. Nontraumatic SAH was identified using a validated approach requiring an inpatient claim for its diagnosis code. Additionally, we required the presence of an procedure code reflecting treatment of a cerebral aneurysm during the same hospitalization to ensure ascertainment of aneurysmal SAH specifically. We used survival statistics to calculate incidence rates and Cox proportional hazards models to evaluate the association between cirrhosis and aneurysmal SAH after adjustment for demographics, stroke risk factors, and comorbidities.

Results: We identified 10,658 (0.6%) patients with cirrhosis from among the 1,778,604 beneficiaries in our sample. The mean age of patients with cirrhosis was 73.5 (±7.8) years, and 48% were female. Over a mean of 4.7 (±2.1) years of follow-up, 4,272 patients were hospitalized with aneurysmal SAH. The annual incidence of aneurysmal SAH in patients with cirrhosis was 0.12% (95% confidence interval [CI], 0.08-0.17%) compared to 0.05% (95% CI, 0.05-0.05%) in patients without cirrhosis. In the adjusted model, cirrhosis was independently associated with aneurysmal SAH (hazard ratio, 2.2; 95% confidence interval, 1.5-3.4).

Interpretation: Cirrhosis was independently associated with an increased risk of aneurysmal SAH among older individuals. Confirmation of these findings may yield opportunities for risk stratification and prevention.